We had never met, but as we talked on the phone I knew she was Googling me. The way she drew out her conjunctions, just a little, that was the tip off  stalling for time as new pages loaded. It was barely audible, but the soft click-click of the keyboard in the background confirmed it. Oh, well, it's the information age. Normally, she'd have to go through my staff first, but I gave her an appointment.

Susan was well spoken and in good shape, an attractive woman in her mid-40s. She had brought her three-year-old to my office, but was ignoring the little monster as he ripped up magazines, threw fish crackers and Cheerios, and stomped them into my rug. I tried to ignore him too, which was hard as he dribbled chocolate milk from his sippy cup all over my upholstered chairs. Eventually his screeching made conversation impossible.

"This is not an acceptable form of behavior, not acceptable at all," was Susan's excruciatingly well-enunciated and perfunctory response to Junior's screaming. The toddler's defiant delight signaled that he understood just enough to ignore her back. Meanwhile, Mom launched into me with a barrage of excruciatingly well-informed questions. I soon felt like throwing Cheerios at her too.

Susan had chosen me because she had researched my education, read a paper I had written, determined my university affiliation and knew where I lived. It was a little too much  as if she knew how stinky and snorey I was last Sunday morning. Yes, she was simply researching important aspects of her own health care. Yes, who your surgeon is certainly affects what your surgeon does. But I was unnerved by how she brandished her information, too personal and just too rude on our first meeting.

Every doctor knows patients like this. They're called "brainsuckers." By the time they come in, they've visited many other docs already  somehow unable to stick with any of them. They have many complaints, which rarely translate to hard findings on any objective tests. They talk a lot. I often wonder, while waiting for them to pause, if there are patients like this in poor, war-torn countries where the need for doctors is more dire.

Susan got me thinking about patients. Nurses are my favorites  they know our language and they're used to putting their trust in doctors. And they laugh at my jokes. But engineers, as a class, are possibly the best patients. They're logical and they're accustomed to the concept of consultation  they're interested in how the doctor thinks about their problem. They know how to use experts. If your orthopedist thinks about arthritis, for instance, in terms of friction between roughened joint surfaces, you should try to think about it, generally, in the same way. There is little use coming to him or her for help if you insist your arthritis is due to an imbalance between yin and yang, an interruption of some imaginary force field or a dietary deficiency of molybdenum. There's so much information (as well as misinformation) in medicine  and, yes, a lot of it can be Googled  that one major responsibility of an expert is to know what to ignore.